The present invention relates to an electrical connector, in which a flat circuit board such as a circuit board member having a board circuit configuration is held with a holding member. In particular, the present invention relates to an electrical connector, in which a flat circuit board such as a circuit board member having a board circuit configuration suitable for high-speed transmission is held with a holding member.
As a conventional board circuit configuration in a circuit member of a connector of this type, for example, there is known a conventional circuit configuration disclosed in Patent Reference. The conventional circuit configuration of Patent Reference 1 is the most common and simple configuration, and has a plurality of transmission paths only on one surface of the circuit board and a grounding plate all over the other surface thereof by plating, without having transmission paths in an inner layer of the circuit board.
Patent Reference: U.S. Patent Application Publication No. 2012-0295453A1
In the conventional circuit configuration disclosed in Patent Reference, a plurality of transmission paths corresponds and is electrically connected to a plurality of pad-like connecting sections arranged along an edge of the circuit board. Each transmission path has a smaller width (a dimension in a direction of the arrangement) than that of the corresponding connecting section. The plurality of transmission paths is arranged so as to repeat the arrangement such as that of one grounding transmission path, two adjacent signal transmission paths, and one grounding transmission path. One grounding transmission path is provided each of both sides of two signal transmission paths that compose a pair of transmission paths.
In the conventional circuit configuration disclosed in Patent Reference, the grounding transmission paths are electrically connected to the grounding plate on the other surface with via holes penetrating through the board. In the pair of transmission paths, the transmission paths are close to each other in the width direction, and the both are connected to corresponding connecting sections of paired connecting sections, and form a pair of transmission paths suitable for transmitting high-speed signals. The pair of connecting sections that is electrically connected to the pair of transmission paths increases the distance in the width direction between the both connecting sections of the pair of connecting sections so as to have large width as described above in order to adjust impedance, corresponding to a thickness of the board defined by itself.
In the conventional circuit configuration disclosed in Patent Reference, however, when the connecting sections have large areas with large width, the distance between the both connecting sections in the width direction is increased. Therefore, although it is possible to adjust and improve the impedance, there are issues as follows.
First, since the connecting sections have a large area, when all of the connecting sections are formed on a circuit board surface by plating, a total plating area has to be increased, which results in higher cost.
Second, the respective connecting sections have a large areas, so that it is possible to fully cover points of contacts with mating terminals. Therefore, even if there is some relative displacement among the contacts in the width direction, since the range of the contacts is large, it is advantageous in view of secure contacts. However, the contact surface pressure has to be small, and thereby there is an issue of lower contact reliability.
In view of the problems described above, an object of the present invention is to provide an electrical connector having a circuit member, which can restrain the plating area as small as possible and achieve high contact reliability under high contact surface pressure, while securing the distance between connecting sections, impedance of which is adjustable.
Further objects and advantages of the present invention will be apparent from the following description of the present invention.